Jelena Ostapenko began the defence of her Korea Open title with a comfortable 6-3 6-3 win over Lara Arruabarrena.
The Latvian's only previous attempt to retain a title resulted in a disappointing first-round loss at this year's French Open, but she had more joy with her second try as she secured progression in just one hour and 14 minutes.
Top seed Ostapenko racked up 32 winners against 2016 Korea Open champion Arruabarrena, but 29 unforced errors contributed to putting her one point away from falling 3-0 down in the second set.
However, the world number 10 managed to force a break and added another two as she set up a meeting with Ekaterina Alexandrova.
Ostapenko said of Arruabarrena: "She's a very good player and very consistent. It was a good match for me, especially for the first round because first rounds are always tough."
Hsieh Su-wei awaits the victor of Ostapenko's match against Alexandrova in the quarter-finals following a 6-2 6-1 triumph over Stefanie Vogele, with Maria Sakkari, Ajla Tomljanovic and Evgeniya Rodina joining her in the last eight.
Second seed Kiki Bertens overcame Luksika Kumkhum 7-6 (9-7) 6-2 and will take on Dalila Jakupovic for the right to face Rodina.